Flight plans of hundreds of travelers were again disrupted on Thursday as poor visibility surrounded New Zealand's Wellington airport for a second night due to fog.

Radio New Zealand said the airport is again hard to see from 100 metres away.

Air New Zealand has advised travelers flying in and out of Wellington to expect another round of delays on Thursday evening.

The flight disruptions were spurred by a low-lying sea fog on Wednesday evening that emanated from Cook Strait island, pushed by gentle southerly winds.

That evening, 29 people spent the night at Wellington Airport.

Airport authorities were forced to cancel, delay or divert a number of flights to Palmerston North or Paraparaumu.

About 4,000 passengers of Air New Zealand have been affected by flight cancellations on Thursday.

Greg Thomas, Wellington Airport spokesman, advised travellers to check with the airport's Web site or their airline for updates since air travel could be disrupted for some time throughout the country.

The thick fog, now on its second evening, has shrouded the entrance to Wellington harbor. Ships going in and out have been forced to sound their foghorns to warn their movements.

Air New Zealand advised domestic travelers to consult the departures information on the company's Web site or call the contact centre on 0800 737 000 for further information.